Method and apparatus for surgical fastening

ABSTRACT

A surgical fastener system includes a plurality of fasteners having a throughbore with a non-circular cross section portion. The fasteners may engage with a splined mandrel that passes through the throughbore of the fasteners and rotates the fasteners relative to the mandrel to move at least one of the fasteners along the mandrel, e.g., along the mandrel&#39;s longitudinal axis. A distal end of the mandrel may be inserted into a material, such as a tissue, prosthetic or other, and a fastener may be deployed from the distal end of the mandrel while the distal end is positioned in the material.

This application is a continuation of U.S. application Ser. No.12/550,618, filed Aug. 31, 2009 which is a continuation of U.S.application Ser. No. 12/354,147, filed Jan. 15, 2009 which is acontinuation of PCT/US2007/015952, filed Jul. 13, 2007 and claims thebenefit of U.S. provisional application No. 60/831,712, filed Jul. 18,2006.

BACKGROUND

1. Field of Invention

This invention relates to methods and apparatus for surgical fastening.

2. Related Art

Surgical fasteners are widely used in many different medical procedures.For example, staples, sutures, clips and other fasteners are commonlyused in laparoscopic and open surgical procedures to secure two or moreportions of tissue, prosthetic, or other material relative to eachother. The fasteners may provide a permanent connection between twoportions, such as between bone and a non-absorbable prosthetic, or mayprovide a more temporary fixation, such as between a mesh prosthetic andmuscle or other tissue to allow tissue ingrowth or other healingprocesses to more securely fixate the mesh relative to the tissue.

For example, U.S. Patent Publication 2004/0049227 to Jervis discloses ahelical fastener and applicator for attaching a prosthesis to tissue,e.g., to attach a mesh prosthetic in a hernia repair procedure. Theapplicator disclosed in Jervis may deploy one or more fasteners having ahelical wire coil shape by using a rotator to rotate and discharge thefasteners from a distal end of the applicator. In one embodiment, astationary stabilizer rod located at an inner portion of the coilfasteners has a thread form that engages with the fasteners and feedsthe fasteners distally as they are rotated.

Other fasteners used to secure mesh in a surgical procedure, such ashernia repair, are disclosed in U.S. Patent Publication 2004/0204723 toKayan and U.S. Patent Publication No. 2005/0171562 to Criscuolo, amongothers. In both Kayan and Criscuolo, the fasteners include a thread formand head on a screw-like structure. These fasteners are also said to bemade of an absorbable material. Thus, the fasteners may degrade and beabsorbed by the body after the surgical procedure is complete.

SUMMARY OF THE INVENTION

In one aspect of the invention, a surgical fastener includes a barrelportion with a helical thread extending from near a distal end of thebarrel portion toward a proximal end of the barrel portion. A headportion may be located at the proximal end of the barrel portion, and athroughbore may extend through the head portion and the barrel portion.The throughbore may include a splined portion, and the barrel portionand the head portion may be formed of a bioabsorbable material. In oneembodiment, the throughbore may have an unsplined portion located at aproximal end of the throughbore. The splined portion may be located at adistal end of the throughbore, and the unsplined portion may extend overapproximately half a length of the throughbore. The head portion of thefastener may include at least one alignment feature adapted to allow aplurality of fasteners to be aligned together on a mandrel. For example,the at least one alignment feature may include a flat portion on oneside of the head portion.

In another aspect of the invention, a surgical fastener includes abarrel portion with a longitudinal axis and a helical thread extendingfrom near a distal end of the barrel toward a proximal end of the barrelportion. A head portion may be attached at the proximal end of thebarrel portion. A throughbore may extend along the longitudinal axisthrough the head portion and the barrel portion, and the barrel portionand head portion may be formed of a bioabsorbable material. In oneembodiment, the distal end of the barrel portion may have a crenellatedtip feature. The crenellated tip may help the distal end of the fastenerpenetrate a material, such as a mesh material and/or may help lead thefastener into a material by allowing the distal end of the fastener toclosely conform to the shape of a mandrel on which the fastener ismounted.

In another aspect of the invention, a surgical fastener system includesa tube having a distal end, a proximal end, and an inner bore with aninternal threaded portion. A plurality of fasteners may be located inthe tube, with each of the fasteners having a barrel portion with anexternal thread and a throughbore extending through the barrel portion.The throughbore may have a portion with a non-circular cross-sectionthat receives and engages with a mandrel also located in the inner bore.The mandrel may have a distal end, and a longitudinal axis and bearranged for rotation about the longitudinal axis. A pusher element maybe adapted to engage with the mandrel for rotation with the mandrel andengage with the internal threaded portion of the inner bore. Thus,rotation of the mandrel about the longitudinal axis may cause rotationof at least one of the fasteners engaged with the mandrel as well asrotation of the pusher element relative to the internal threadedportion. Rotation of the pusher element may cause the pusher element tomove along the direction of the longitudinal axis in the inner bore,e.g., to urge fasteners on the mandrel to move distally. In oneembodiment, the mandrel has a cruciform shape in a cross-sectionperpendicular to the longitudinal axis, and the non-circular crosssection for each of the fasteners is a cruciform shape complementary tothe cruciform shape cross section of the mandrel.

In another aspect of the invention, a surgical fastener system includesa tube having a distal end, a proximal end, and an inner bore. Aplurality of fasteners may be located in the tube, with each of thefasteners having a barrel portion with an external thread and athroughbore extending through the barrel portion. The throughbore mayhave a portion with a non-circular cross-section, and a mandrel alsolocated in the inner bore may pass through and engage with thethroughbore of the plurality of fasteners. The mandrel may have a distalend, and a longitudinal axis and be arranged for rotation about thelongitudinal axis. Rotation of the mandrel about the longitudinal axismay cause rotation of at least one of the fasteners engaged with themandrel and deployment of the at least one fastener from the distal endof the tube. None of the fasteners proximal of the distalmost fastenermay engage with the inner bore of the outer tube so as to resist axialor rotational movement of the fasteners relative to the tube.

In another aspect of the invention, a surgical fastener system includesa tube having a distal end, a proximal end, and an inner bore. Aplurality of fasteners may be located in the tube, with each of thefasteners having a barrel portion with an external thread and athroughbore extending through the barrel portion. The throughbore mayhave a portion with a non-circular cross-section. A mandrel may belocated in the inner bore and adapted to pass through the throughbore ofthe plurality of fasteners and engage with the non-circularcross-sectional portion of at least one of the plurality of fasteners.The mandrel may have a distal end, and a longitudinal axis and bearranged for rotation about the longitudinal axis and movement along thelongitudinal axis relative to the tube. Rotation of the mandrel aboutthe longitudinal axis may cause rotation of at least one of thefasteners engaged with the mandrel and deployment of the at least onefastener from the distal end of the tube.

These and other aspects of the invention will be apparent from thefollowing description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the invention are described below with reference toillustrative embodiments, wherein like numerals reference like elements,and wherein:

FIG. 1 is a perspective view of a fastener applier in accordance withaspects of the invention;

FIG. 2 shows a partial cross section of the shaft of the applier of FIG.1;

FIG. 3 is an end view of the distal end of the applier of FIG. 1;

FIG. 4 shows a perspective view of the distal end of the mandrel;

FIGS. 5-7 show a cross-sectional view of the distal end of the applierin various stages of deploying a fastener;

FIGS. 8-10 show a cross-sectional view of the distal end of an applierof an alternate embodiment in various stages of deploying a fastener;

FIG. 11 shows a side view of a fastener in accordance with aspects ofthe invention;

FIG. 12 shows a bottom view of the FIG. 11 fastener;

FIG. 13 shows a top perspective view of the FIG. 11 fastener;

FIG. 14 shows a cross-sectional view of the FIG. 11 fastener;

FIG. 15 shows a left-side, cross-sectional view of the handle portion ofthe fastener applier; and

FIG. 16 shows a right-side, cross-sectional view of the handle portionof the fastener applier.

DETAILED DESCRIPTION

It should be understood that aspects of the invention are describedherein with reference to the figures, which show illustrativeembodiments in accordance with aspects of the invention. Theillustrative embodiments described herein are not necessarily intendedto show all aspects of the invention, but rather are used to describe afew illustrative embodiments. Thus, aspects of the invention are notintended to be construed narrowly in view of the illustrativeembodiments. In addition, it should be understood that aspects of theinvention may be used alone or in any suitable combination with otheraspects of the invention.

In one aspect of the invention, a fastener applying system may include aplurality of fasteners that each include a barrel portion with anexternal thread and a throughbore extending through the barrel portion,e.g., along the barrel's longitudinal axis. The fasteners may eachinclude a head portion that may be wider than the barrel portion and/orthe external thread on the barrel. The fasteners may be arranged along amandrel that has a splined portion and extends through the throughboreof the fasteners. At least a part of the throughbore of each fastenermay have an internally splined portion that engages with the splinedportion of the mandrel. The mandrel may rotate about its longitudinalaxis so as to cause the fasteners to rotate. A pusher element at aproximal end of the fasteners may also engage with the mandrel andengage with an internal threaded portion of a tube that houses thefasteners. Thus, as the mandrel, fasteners and pusher element rotaterelative to the tube, the pusher element may be driven to move distallyon the mandrel, pushing the fasteners to move distally as well.

The fastener system may be used to deploy the fasteners in a subjecttissue or other material, e.g., to secure a mesh to a muscle tissue in ahernia repair procedure. To deploy a fastener, a leading or distal endof the mandrel may first be positioned adjacent a subject material. Inone illustrative embodiment, the mandrel may be inserted into thesubject material, e.g., a pointed end of the mandrel may be insertedinto the subject material. The mandrel may rotate at least a fastenerlocated nearest the distal end of the mandrel so as to advance thefastener into the subject material. The distalmost and other fastenerson the mandrel may be fed toward the distal end of the mandrel, e.g., bya pusher element that rotates with the mandrel and engages a threadedportion in an outer tube so that the pusher element is forced distallyon the mandrel. As the distalmost fastener is rotated, the externalthread on the fastener barrel may engage with the subject material(e.g., mesh, tissue and/or other) and draw the fastener into thematerial. A head provided on the fastener may aid in seating thefastener at the material surface, aid in holding two or more materialstogether, and/or prevent overinserting the fastener into the material.

FIG. 1 shows a fastener applier 100 and associated fasteners in anillustrative embodiment. The applier 100 includes a handle 1 and a shaft2 extending distally from the handle 1. The shaft 2 houses a pluralityof fasteners 4 on a mandrel 5 that are arranged so that the fasteners 4rotate with the mandrel 5 when the mandrel 5 rotates about itslongitudinal axis, but are otherwise generally free to move axiallyalong the mandrel 5. A pusher element 3 at a proximal end of thefasteners 4 is arranged like the fasteners 4 to rotate with the mandrel5, and is movable axially along the mandrel 5. As shown in the partialcross section of FIG. 2, the pusher element 3 also engages with aninternally threaded portion of the shaft 2 so that as the pusher element3 rotates with the mandrel 5, the pusher element 3 moves distally alongthe mandrel 5, pushing the fasteners 4 distally. The pusher element 3may take any suitable form, and in this embodiment includes acylindrical plug with thread elements that engage with the internalthreads on the shaft 2. In addition, the pusher element 3 need not berotated by the mandrel 5, but instead may be rotated by a separate driveelement. In other embodiments, the pusher element 3 need not rotate, andinstead may urge fasteners 4 to move distally in other ways, such as bya spring, a tape drive, or other arrangement. A trigger or otheractuator 6 on the handle 1 may be operated by a user to rotate themandrel 5, and to move the mandrel 5 distally relative to the shaft 2,e.g., so that a pointed end on the mandrel 5 is exposed from the distalend of the shaft 2. Once the distalmost fastener 4 is deployed, themandrel 5 may retract within the shaft 2.

As can be seen in FIG. 3, in this embodiment the shaft 2 has a tubularshape with an approximately circular cross section. The inside surfaceof the shaft 2 may (or may not) engage with the fasteners 4, e.g., tohelp align the fasteners 4 and prevent wobbling of the mandrel 5 duringrotation, and allow the fasteners 4 to move axially along the mandrel 5.As can be seen in FIGS. 3 and 4, the mandrel 5 in this embodiment has acruciform-shaped cross section, i.e., having four longitudinal splinesarranged symmetrically around the mandrel 5. However, the mandrel 5 insome embodiments may have other cross sectional shapes, such ashexagonal, square, star-shaped or other cross section so as to engagewith corresponding surfaces on the fasteners 4. In other embodiments,the mandrel 5 may have two or more longitudinally extending portionsthat engage with fasteners 4, such as a pair of prongs that extendlongitudinally through the shaft 2 and through corresponding holes orgrooves in the fasteners 4. Also, although in this embodiment all of thefasteners on the mandrel 5 are rotated with the mandrel, in otherarrangements, the mandrel 5 may only rotate the distalmost fastener 4,and trailing fasteners may not rotate. For example, the mandrel 5 mayonly include a splined portion near a distal end of the shaft, and moreproximal portions of the mandrel 5 may have a smooth cylindrical surfaceor other arrangement that does not engage with fasteners 4 so as tocause rotation of the fasteners.

FIGS. 5-7 show a fastener being deployed by the applier 100 in FIG. 1.In FIG. 5, a user may position the distal end of the shaft 2 against asubject material, such as a mesh prosthetic 81 positioned on a muscletissue 82. At this point, the mandrel 5 and the distalmost fastener 4may be located within the shaft 2 (although in other embodiments, themandrel 5 and/or the fastener 4 may be exposed). Actuation of theapplier 100 may initially extend the mandrel 5 outside of the distal endof the shaft 2 so that the mandrel 5 penetrates the mesh 81 and/ortissue 82. In this embodiment, the mandrel 5 has a sharpened tip to aidin puncturing the subject material, but other arrangements are possible,such as a gimlet feature, a conical tip, blunt end or other on themandrel's distal end. Alternately, the mandrel 5 may not penetrate thesubject material, but rather may only press against the material or bepositioned adjacent the material, e.g., in embodiments in which themandrel 5 does not extend distally from the shaft 2. Also in thisembodiment, the mandrel 5 extends into the subject material withoutrotation, but in some embodiments, the mandrel 5 may rotate as itpunctures the subject material, e.g., to aid in entry into the material.During distal extension of the mandrel 5, the pusher element 3 andfasteners 4 may remain stationary. The distalmost fastener 4 may be heldin place by a restriction element 21 of the shaft 2. The restrictionelement 21 may include a narrowed diameter portion of the shaft 2, oneor more bumps, fingers, spring loaded elements or other features to helpretain the fasteners 4 in the shaft 2 as the mandrel 5 is extended. (Itshould be understood that exposure of the mandrel 5 from the distal endof the shaft 2 may occur by having the distal end of the shaft 2 retractproximally, e.g., as the shaft's distal end is pressed against thematerial, in addition to, or instead of, having the mandrel 5 movedistally.)

With the mandrel 5 extended into the material as shown in FIG. 6, themandrel 5 may be rotated about its longitudinal axis. This causes thepusher element 3 and fasteners 4 to rotate with the mandrel 5 and movedistally as the pusher element 3 moves distally. As the distal tip ofthe distalmost fastener 4 emerges from the shaft 2, the fastener 4penetrates the mesh 81 and the tissue 82. In addition to the force ofthe pusher element 3 pushing on the stack of fasteners 4 on the mandrelto urge the distalmost fastener 4 past the restriction element 21, theexternal thread on the fastener 4 may engage with the mesh 81 and tissue82 and help to pull the fastener into the material. With suitablerotation of the fastener 4, the fastener 4 is fully inserted into thematerial as shown in FIG. 7. The fastener 4 may then be disengaged fromthe mandrel 5, as the mandrel 5 and/or shaft 2 are pulled away from thefastener to deploy the fastener 4 from the applier 100. The mandrel 5may be retracted into the shaft 2 to the position shown in FIG. 5, readyto deploy a next fastener in the applier 100. Note that the nextdistalmost fastener 4 is maintained in the shaft by the restrictionelement 21, e.g., so the fastener 4 is not dropped from the shaft 2until forced out by the pusher element 3.

FIGS. 8-10 show another illustrative embodiment of an applier 100 thatuses a different restriction element 21 than the above embodiment. Inthis embodiment, the restriction element 21 includes an inner tube thathas spring fingers, a swaged portion or other restriction feature. Theinner tube may or may not be movable in the shaft 2.

Fasteners 4 used with the applier 100 may have any suitable arrangement,as will be appreciated by those of skill in the art. FIGS. 11-14 showvarious views of a fastener 4 in an illustrative embodiment. FIG. 11shows a side view of the fastener 4, which has a head 41, an externalhelical thread 42 and a barrel portion 43. The head 41 may have anysuitable shape and/or size, and in this embodiment has a generally flatdistal face near the thread 42 and a rounded proximal face. The externalthread 42 may have a diameter d that is close in size to the head 41 inthe view shown in FIG. 11. The external thread 42 may make approximately3½ revolutions around the barrel portion 43, although in otherembodiments, the thread 42 may make fewer or more revolutions. Theexternal thread 42 may also taper down near the distal end of the barrelportion 43. This tapering may aid in the fastener's penetration into asubject material, such as a mesh 81. In this embodiment, the thread 42also tapers at the proximal end of the barrel portion 43, e.g., tohaving a zero crest height, at or before the head 41, but may insteadmaintain a relatively constant diameter to a point at which the thread42 joins the head 41. Having the thread 42 extend to the head 41 mayhelp allow the fastener 4 to be removed from a material, such as mesh81, by simply rotating the fastener 4 in a reverse direction. On theother hand, such a thread arrangement may permit the fastener 4 to be“overdriven” and pass through a mesh 81 or other material to anundesired depth. Having a gap between the proximal most end of thethread 42 and the head 41 (as shown in FIG. 11) may help stop thefastener insertion at a material surface, and may also cause somematerials, such as a mesh 81, to be captured between the thread 42 andthe head 41. Other variations to the external thread 42 may be made,such as different thread pitches, a variable thread pitch, differentthread face angles (leading and/or trailing faces), thread crest shapes(pointed, flat as shown, rounded, etc.), two or more threads, and so on.The external thread 42 may also have the distal most portion of thethread 42 extend forward of the barrel portion 43, e.g., forming agimlet, hook or prong portion that may aid in leading the fastener 4into a material. Also, a pitch of the internal threaded portion of theshaft 2 that engages the pusher element 3 may be the same as, longer, orshorter than a pitch of the external thread 42. In this illustrativeembodiment, the thread pitch of the internally threaded portion of theshaft 2 is longer than the thread pitch of the external thread 42, e.g.,to help aid in disengaging the fasteners 4 from the mandrel 5 duringdeployment. In short, any suitable external thread 42 arrangement may beused in some aspects of the invention.

In one aspect of the invention, the barrel portion may have acrenellated front face 431. For example, as shown in FIG. 11, the barrelportion 43 may have a tapered distal end. If the barrel portion 43 has acylindrical or conical form, the tapered distal end may terminate in acrenellated forward edge 431 in which distalmost portions of the forwardedge 431 are received in grooved portions of the mandrel 5 between thesplines. This arrangement may aid in penetration of the fastener 4 in amaterial, e.g., because a leading part of the distal end of the barrelportion 43 first penetrates the material, leading the way for thetrailing part of the distal end. It has also been found in someembodiments that the crenellated front face 431 may help cut throughmaterial, e.g., in a way similar to a serrated blade. Other arrangementsfor the distal end of the tack are possible, including a “fish mouth”type feature in which the distal end of the barrel portion 43 has a “V”shaped notch. Alternately, the distal end of the barrel portion 43 mayhave a sharp leading edge to help penetrate material.

In another aspect of the invention and as shown in FIGS. 12-14, thefasteners may have a throughbore 44 extending through the barrel portion43 and the head 41. The throughbore 44 may extend along a longitudinalaxis of the barrel portion 43, and provide a pathway through thefastener 4. In one aspect of the invention, the throughbore 44 may havea splined cross section throughout its entire length that mates with themandrel 5. However, in another embodiment, only a distal portion of thethroughbore 44 may include a splined cross section. A proximal portionof the throughbore may have a larger diameter than the distal splinedportion, e.g., so that the proximal portion does not engage with themandrel 5. The proximal portion may have any shape or size, e.g., mayhave a smooth cylindrically shaped bore. By arranging the throughbore 44so that only a distal portion of the fastener 4 engages with the mandrel5, the fastener 4 may be more easily disengaged from the mandrel 5during deployment. However, it is possible that the throughbore 44 besplined along its entire length, or may be splined only at the proximalend.

As shown in FIGS. 13 and 14, the head 41 of the fastener 4 may includeat least one flat side surface 411 or other feature which may help inaligning a plurality of fasteners 4 when mounted on a mandrel 5.Alignment of the fasteners 4 may be important, for example, when thefasteners 4 have a non-symmetrical shape, e.g., include an angled distalface. Of course, an alignment feature may take other forms, such as abump, notch, groove, hole, marking or other.

The fastener may be made of any suitable biocompatible material, such asan absorbable material (e.g., PLA or other), a non-absorbable metal orplastic (e.g., titanium), or any other material or combination ofmaterials. Further, the fasteners 4 may be made of any suitable size,e.g., about ¼ inch long and about ⅛ inch in diameter with a throughborediameter of about 1/32 inch.

The applier 100 may deploy fasteners 4 using a manually operatedmechanism, a motorized mechanism, or a combination of manual andmotorized. FIGS. 15 and 16 show left and right side views, respectively,of a manually-operated mechanism for the applier 100 of FIG. 1. In thisillustrative embodiment, the handle 1 includes a trigger 6 that has twooperable trigger levers 61 and 62 that both pivot about a trigger pivot63. The outer trigger lever 61 is exposed and is gripped by a user,whereas the inner trigger lever 62 is housed inside of the outer triggerlever 61. Both trigger levers 61 and 62 are urged to a starting positionshown in FIG. 15 by a spring 64 or other suitable resilient member. Theouter trigger lever 61 includes a mandrel drive rack 611 that has teethwhich engage with a mandrel drive pinion 11. Accordingly, as the outertrigger lever 61 is moved toward the handle 1, the mandrel drive rack611 causes the mandrel drive pinion 11 to rotate (in a counterclockwisedirection as shown in FIG. 15). This rotates a mandrel drive cam 111which is fixed to the pinion 11 and engages with pin 121 on a mandrelslider 12. When the outer trigger lever 61 is in the starting position,a notch 112 in the mandrel drive cam 111 is engaged with the pin 121,allowing the mandrel slider 12 to move proximally (to the right in FIG.15) under the bias of a spring 13. However, as the outer trigger lever61 is depressed and the mandrel drive cam 111 rotates, the cam 111pushes the pin 121 distally, causing the mandrel slider 12 to movedistally against the bias of the spring 13. Since the mandrel slider 12is coupled to the mandrel 5, the mandrel 5 moves distally with themandrel slider 12. The mandrel slider 12 is only moved distally untilthe notch 112 is cleared from the pin 121. Thereafter, the mandrelslider 12 and mandrel 5 remain stationary.

During initial movement of the outer trigger lever 61 from the startingposition, the inner trigger lever 62 remains stationary. However, uponfurther depression of the outer trigger lever 61, the outer triggerlever 61 contacts the inner trigger lever 62 so the inner trigger lever62 rotates about the trigger pivot 63 as well. The inner trigger lever62 includes a mandrel drive rack 622 that engages with a drive pinion 14(see FIG. 16). Movement of the inner trigger lever 62 therefore causesrotation of the drive pinion 14 and an associated bevel gear 141, whichis engaged with a complementary bevel gear of a clutch 15. As a result,rotation of the drive pinion 14 causes the bevel gear 141 to rotate theclutch 15 (e.g., in a clockwise direction looking from the handle 1 downthe shaft 2). The clutch 15 is engaged with the mandrel 5, and thusrotation of the clutch 15 in the clockwise direction causes the mandrel5 to rotate clockwise as well. Continued depression of the triggerlevers 61 and 62 rotates the mandrel 5 and causes a fastener 4 to bedeployed as described above. A pawl 16 is arranged to engage with themandrel drive rack 611 so that once fastener rotation begins (i.e., oncethe outer trigger 61 contacts the inner trigger 62 and the clutch 15rotates the mandrel 5), the trigger levers 61 and 62 cannot return tothe starting position of FIG. 15 until the trigger levers 61 and 62 arecompletely depressed. Upon complete depression of the trigger levers 61and 62, the pawl 16 may clear the mandrel drive rack 611, allowing themandrel drive rack 611 and trigger levers 61 and 62 to return to thestarting position. Return movement of the trigger levers 61 and 62 maycause the mandrel drive pinion 11 and the drive pinion 14 to bebackdriven. As a result, the notch 112 returns to engagement with thepin 121, causing the mandrel slide 12 and mandrel 5 to be movedproximally by the spring 13. Although the bevel gear 141 may rotate inreverse during trigger return, the clutch 15 may prevent the mandrel 5from rotating. Instead, the mandrel 5 remains stationary during triggerreturn.

Deployment of a distal most fastener 4 may occur during the stroke ofthe trigger levers 61 and 62, i.e., before the trigger levers 61 and 62are completely depressed and the pawl 16 clears the mandrel drive rack611. This arrangement may help ensure that the fastener 4 is disengagedfrom the mandrel 5 before rotation of the mandrel 5 stops and themandrel 5 is retracted. For example, the fastener 4 may be arranged todisengage from the mandrel 5 upon three revolutions of the mandrel 5.However, the mandrel 5 may be arranged to rotate 3½ revolutions beforestopping. After the mandrel 5 stops rotating, the pawl 16 may bearranged to require further depression of the trigger levers 61 and 62before the pawl 16 clears the rack 611. During this motion of thetrigger levers 61 and 62, other functions may be performed, such asactuating a counter to indicate that a fastener has been deployed. Inone embodiment, a display of fasteners deployed and/or fastenersremaining may be provided on the handle 1, e.g., on an LCD or LEDdisplay.

Having thus described several aspects of at least one embodiment of thisinvention, it is to be appreciated various alterations, modifications,and improvements will readily occur to those skilled in the art. Suchalterations, modifications, and improvements are intended to be part ofthis disclosure, and are intended to be within the spirit and scope ofthe invention. Accordingly, the foregoing description and drawings areby way of example only.

What is claimed is:
 1. A surgical fastener system including: a tubehaving a distal end, a proximal end, and an inner bore; a plurality offasteners located in the tube, each of the fasteners having a barrelportion with an external thread and a throughbore extending through thebarrel portion, the throughbore having a portion with a non-circularcross-section; a mandrel located in the inner bore and adapted to passthrough the throughbore of each of the plurality of fasteners, themandrel adapted to engage with the non-circular cross-sectional portionof the plurality of fasteners, the mandrel having a distal end, aproximal end, and a longitudinal axis extending therebetween, themandrel being arranged for rotation about the longitudinal axis relativeto the tube and arranged for movement along the longitudinal axisrelative to the tube such that the distal end of the mandrel isextendable from the distal end of the tube, wherein movement of themandrel along the longitudinal axis does not cause ejection of adistalmost fastener of the plurality of fasteners from the tube; and ahandle attached to the proximal end of the tube, the handle including anactuator adapted to cause the distal end of the mandrel to move andextend from the distal end of the tube, the actuator adapted to causethe mandrel to rotate about the longitudinal axis relative to the tubeto deploy the distalmost fastener of the plurality of fasteners, theactuator being adapted to retract the distal end of the mandrel into thetube after deployment of the distalmost fastener; wherein rotation ofthe mandrel about the longitudinal axis causes rotation of thedistalmost fastener engaged with the mandrel and deployment of thedistalmost fastener from the distal end of the tube.
 2. The system ofclaim 1, wherein the tube includes a threaded portion of the inner bore.3. The system of claim 2, further comprising a pusher element adapted toengage with the mandrel for rotation with the mandrel, the pusherincluding thread elements adapted to engage with the internal threadedportion of the inner bore such that rotation of the pusher element withthe mandrel causes the pusher element to move in a direction along thelongitudinal axis and to move the plurality of fasteners along thelongitudinal axis.
 4. The system of claim 3, wherein the plurality offasteners are arranged to move freely along the mandrel in the directionof the longitudinal axis.
 5. The system of claim 3, wherein movement ofthe pusher element along the mandrel in the direction of thelongitudinal axis urges the distalmost fastener on the mandrel to bedisengaged from a distal end of the mandrel.
 6. The system of claim 1,wherein the mandrel has a sharpened distal end or a gimlet at the distalend.
 7. The system of claim 1, wherein the mandrel has a cruciform shapein a cross-section perpendicular to the longitudinal axis.
 8. The systemof claim 7, wherein the non-circular cross section for each of thefasteners is a cruciform shape complementary to the cruciform shapecross section of the mandrel.
 9. The system of claim 1, wherein none ofthe fasteners located proximally of the distalmost fastener contacts theinner bore of the tube so as to resist axial or rotational movement ofthe fasteners relative to the tube.
 10. The system of claim 1, whereinthe actuator includes a manually operated trigger.
 11. The system ofclaim 1, wherein each of the fasteners includes a head portion at aproximal end of the barrel portion, the head portion having a size in adirection transverse to the throughbore that is larger than a size ofthe barrel portion.
 12. The system of claim 1, wherein none of thefasteners located proximally of the distalmost fastener contacts theinner bore of the tube so as to resist axial or rotational movement ofthe fasteners relative to the tube.
 13. A surgical fastener systemincluding: a tube having a distal end, a proximal end, an inner borewith an internal threaded portion, and a non-threaded restrictionelement at the distal end; a plurality of fasteners located in the tube,each of the fasteners having a barrel portion with an external threadand a throughbore extending through the barrel portion, the throughborehaving a portion with a non-circular cross-section; a mandrel located inthe inner bore and adapted to pass through the throughbore of theplurality of fasteners, the mandrel adapted to engage with thenon-circular cross-sectional portion of at least one of the plurality offasteners, the mandrel having a distal end, a proximal end, and alongitudinal axis extending therebetween, the mandrel being arranged forrotation about the longitudinal axis relative to the tube; and a pusherelement adapted to engage with the mandrel for rotation with themandrel, the pusher element including thread elements adapted to engagewith the internal threaded portion of the inner bore, wherein rotationof the mandrel relative to the tube causes the pusher element to move ina direction along the longitudinal axis and to move the plurality offasteners along the longitudinal axis relative to the tube; wherein onlyrotation of the mandrel about the longitudinal axis, and not movement ofthe mandrel along the longitudinal axis relative to the tube, causesrotation of a distalmost fastener of the plurality of fasteners engagedwith the mandrel and deployment of the distalmost fastener from thedistal end of the tube, and wherein prior to deployment, the distalmostfastener is positioned to engage with the non-threaded restrictionelement to resist axial movement of the distalmost fastener relative tothe tube, and wherein prior to deployment of the distal most fastenerfrom the distal end of the tube, none of the fasteners proximal of thedistalmost fastener engages with the restriction element or the innerbore of the tube so as to resist axial or rotational movement of thefasteners relative to the tube.
 14. A surgical fastener systemincluding: a tube having a distal end, a proximal end, and an inner borewith an internal threaded portion; a plurality of fasteners located inthe tube, each of the fasteners having a barrel portion with an externalthread and a throughbore extending through the barrel portion, thethroughbore having a portion with a non-circular cross-section; amandrel located in the inner bore and adapted to pass through thethroughbore of the plurality of fasteners, the mandrel adapted to engagewith the non-circular cross-sectional portion of at least one of theplurality of fasteners, the mandrel having a distal end, a proximal end,and a longitudinal axis therebetween, the mandrel being arranged forrotation about the longitudinal axis relative to the tube; and a pusherelement adapted to engage with the mandrel for rotation with themandrel, the pusher including thread elements adapted to engage with theinternal threaded portion of the inner bore; wherein rotation of themandrel about the longitudinal axis relative to the tube causes rotationof at least one of the plurality of fasteners engaged with the mandreland rotation of the pusher element relative to the internal threadedportion, wherein rotation of the pusher element and engagement of thethread elements with the internal threaded portion causes the pusherelement to move along the direction of the longitudinal axis in theinner bore, and wherein none of the fasteners located proximally of adistalmost fastener of the plurality of fasteners contacts the innerbore of the tube so as to resist axial or rotational movement of thefasteners relative to the tube.
 15. The system of claim 14, wherein theplurality of fasteners are arranged to move freely along the mandrel inthe direction of the longitudinal axis.
 16. The system of claim 14,wherein the pusher element is arranged to move freely along the mandrelin the direction of the longitudinal axis.
 17. The system of claim 14,wherein movement of the pusher element along the mandrel in thedirection of the longitudinal axis urges a distalmost fastener on themandrel to be disengaged from a distal end of the mandrel.
 18. Thesystem of claim 14, wherein the mandrel has a sharpened distal end or agimlet at the distal end.
 19. The system of claim 14, wherein themandrel has a cruciform shape in a cross-section perpendicular to thelongitudinal axis.
 20. The system of claim 19, wherein the non-circularcross section for each of the fasteners is a cruciform shapecomplementary to the cruciform shape cross section of the mandrel. 21.The system of claim 14, further comprising a handle attached to theproximal end of the tube.
 22. The system of claim 21, wherein the handleincludes an actuator adapted to cause the mandrel to rotate about thelongitudinal axis.
 23. The system of claim 22, wherein the actuatorincludes a manually operated trigger.
 24. The system of claim 22,wherein the actuator is adapted to cause the distal end of the mandrelto extend from the distal end of the tube.
 25. The system of claim 14,wherein each of the fasteners includes a head portion at a proximal endof the barrel portion, the head portion having a size in a directiontransverse to the throughbore that is larger than a size of the barrelportion.
 26. A surgical fastener system including: a tube having adistal end, a proximal end, and an inner bore with an internal threadedportion; a plurality of fasteners located in the tube, each of thefasteners having a barrel portion with an external thread and athroughbore extending through the barrel portion, the throughbore havinga portion with a non-circular cross-section; a mandrel located in theinner bore and adapted to pass through the throughbore of the pluralityof fasteners, the mandrel adapted to engage with the non-circularcross-sectional portion of at least one of the plurality of fasteners,the mandrel having a distal end, a proximal end, and a longitudinal axistherebetween, the mandrel being arranged for rotation about thelongitudinal axis relative to the tube; a handle attached to theproximal end of the tube, the handle including an actuator adapted tocause the mandrel to rotate about the longitudinal axis and to cause thedistal end of the mandrel to move and extend from the distal end of thetube; and a pusher element adapted to engage with the mandrel forrotation with the mandrel relative to the tube, the pusher elementincluding thread elements adapted to engage with the internal threadedportion of the inner bore; wherein rotation of the mandrel about thelongitudinal axis causes rotation of the at least one of the pluralityof fasteners engaged with the mandrel and rotation of the pusher elementrelative to the internal threaded portion, and wherein rotation of thepusher element and engagement of the thread elements with the internalthreaded portion causes the pusher element to move along the directionof the longitudinal axis in the inner bore and to move the plurality offasteners relative to the tube.